Good sources of information on carbon fiber

[Mark Davison]

Originally Posted by FastCanon

Mark, how much do you weigh? I can see your concern if you're above 200 lb because a lot of the products out there have a weight limit.

Like others have mentioned, you're most likely going to be in a bicycle accident than having your failed carbon frame. You'll more likely going to have a blown tire going downhill than a failed carbon frame. You'll more likely going to crash into another person than a failed carbon frame. You'll more likely going to get into a car accident than a failed carbon frame. You'll more likely going to get robbed than a failed carbon frame. I think you get the gist. But can a carbon frame fail? Yes. We all know someone who have been killed while biking, but it wasn't because of a failed carbon frame.

I weight 180 in fit form, have been up to 210. I'm 6' 3".

Touring the total load is probably 220 with gear and extra water.

[Mark Davison]

Originally Posted by mstateglfr

Edited that post to these 3 things because they stood out.

- agreed, it's nice to have a connection to the bike and who is creating the frame. That can lead to trust for sure, and that trust may or may not be deserved. Many builders aren't materials specialists, structural engineers, etc. They should have an expert knowledge on the products they use, but even that will likely come from marketing litrrature and industry formed relationships(that hold biases).

- totally agree about PL having industry experts. This thread alone had valuable insight from a carbon fork designer.

- you may be appalled by the lack of high quality consumer info about the robustness of components, but is that really unique to CF products? It it even unique to this industry?
The answer to both of those questions is - no.
You expect something that is atypical.

• CF forks, seatpost, and handlebars are constantly videoed undergoing fatigue testing. YouTube is flooded with these videos and has been for the last 15+ years. Is that not enough for you?
  If that isn't enough for you, then look into the testing certification standards the forks and components must pass. If that testing is meaningful to you, then there ya go- data you expect.

• If it isn't meaningful to you because you don't think the testing is realistic or applicable to riding, then maybe look into consumer reviews, long term tests, and industry insight. That is what you are doing when you talk with hampco, so clearly it's good enough.

• I can't get consumer info on the robustness of all sorts of things I own, even things I trust for safety. Or what safety info does exist, it's manufacturer generated or it is certified as passing established testing. So same as a carbon fork or components.
  Do you do this much 'investigation' for everything you buy that is associated to your safety? How often is data both readily available and meets your arbitrary standard of applicability and thoroughness?

• My main road bike is a Columbus Zona steel frame and fork I built 6 years ago in a local class. I trusted the builder to spec it with tubing that is light, easy to work with, reliable, and long lasting once built into a frameset.
  My main gravel bike is a small batch production Reynolds 853 and cromo frame with carbon fork. The designer had to spec overbuilt tubes and an extremely robust fork in order to pass fatigue/impact testing.
  One of those frame and fork combos was actually designed to pass testing, but your posts seem to say you would trust the one that isn't built to pass testing standards.

Maybe take the first step and just call it 'CF' like everyone else? See how that feels, and go from there.

When you buy a traditional metal custom frame there are three things to think about:

the quality of the tubing,
the quality of the design,
the quality of the assembly (mitering, brazing or welding)

The tubing quality is determined and managed by the tubing manufacturer, not the frame maker.

It is absolutely true that frame makers usually aren't engineers. At best they operate within industry standard practices for frame design (and tubing selection) which leave a safety margin. They do make mistakes from time to time, and it has taken the independent builders a little while to figure out what tubing is necessary for disc brakes.

The quality of the assembly is where you hope direct contact builds mutual regard and trust.

Note that on a traditional frame, questions like "what clamping force will the top tube withstand" can be answered based on the tubing used and standard engineering, and requires trust in the tubing manufacturers QA.

Questions about things like "are the welds weak", or "has the tubing been weakened by the application of too much heat" are connected with the skill of the frame maker. Here you depend on the reputation of the frame maker.

So I can't answer one of your questions, i.e. would I trust the frame you made or the one which was specified to meet a demanding test standard.
If the two frames are constructed with equal quality joints, then I would trust the one designed to the high test standard more. If you are a novice welder and you welded both frames and your welds are visibly sloppy, with gaps, I wouldn't trust either frame.

I can't find any documentation online about what test standards Enve is using for forks.

I'm going to continue to irritatingly use CFRP. The properties of the composite are not the same as the constituents, and I have noticed that the shortened form "carbon fiber" leads people to incorrect intuitions about the nature of the composite. For example, they believe that carbon fiber is inert, so that galvanic corrosion cannot occur in CFRP bicycles. They believe that carbon fibers are incredibly strong, so that a CFRP bicycle frame is inherently stronger than a steel one. They believe that CFRP cannot be sensitive to UV light exposure or chemical pollution, so CFRP frames should have an infinite shelf life, no matter how stored. Alas, the poor noble carbon fibers are embedded in lowly epoxy. Perhaps I should agree to call these composite frames "carbon fiber" half the time and "plastic" half the time.

I am purposely acting as a gadfly or devil's advocate in order to pull out comments from the real experts, as opposed to the CF fanboys.

Certainly I don't make this much effort to investigate everything I purchase. This is a one time special effort because I really want lightweight strong bicycle components, but I detect marketing BS around CFRP use in cycling components and would like to get to the bottom of things.

Here's a diatribe from a local bike shop, based on a mechanic's point of view:
https://www.rideyourbike.com/carbonfiber.shtml

[rallizes]

Lol

[fourflys]

Originally Posted by Mike Lopez

There have always been doubters and I long ago gave up trying to convince them otherwise. If you feel the need to worry about your composite parts while riding then don't use them. You're supposed to be enjoying the ride! Not worrying about what may break underneath you. As others have said, you're much more likely to get in another manner.

If you're afraid of the water, stay out of the pool.

pretty sure this, from THE carbon expert on the forum, sums it up nicely.. if Mike Lopez's comments doesn't convince you, not sure why anyone else would engage (other than banter I guess)..

[krooj]

Originally Posted by Mark Davison

I am one of the authors of the diagramming program Visio.

Forget the carbon talk - what is up with this space? I've been on a Mac since I can remember, but Omnigraffle held real promise in the early 2000s and somehow failed to make the leap to web, leaving us with garbage like Gliffy. Even Omnigraffle development seems to have slowed to a crawl: they relied too heavily on 3rd party stencils rather than just doing the hard work of creating quality components to bundle with the tool :/

[fourflys]

Originally Posted by krooj

Forget the carbon talk - what is up with this space? I've been on a Mac since I can remember, but Omnigraffle held real promise in the early 2000s and somehow failed to make the leap to web, leaving us with garbage like Gliffy. Even Omnigraffle development seems to have slowed to a crawl: they relied too heavily on 3rd party stencils rather than just doing the hard work of creating quality components to bundle with the tool :/

wow, that's a whole lotta nerdy words in that post, even for this group..

just kidding, but seriously, I only understand the Mac reference..

[Mark Davison]

Originally Posted by krooj

Forget the carbon talk - what is up with this space? I've been on a Mac since I can remember, but Omnigraffle held real promise in the early 2000s and somehow failed to make the leap to web, leaving us with garbage like Gliffy. Even Omnigraffle development seems to have slowed to a crawl: they relied too heavily on 3rd party stencils rather than just doing the hard work of creating quality components to bundle with the tool :/

I haven’t followed the diagramming “space” since I retired from Visio in 1998. We considered porting Visio to the Mac, but the business analysts concluded the potential increase in profits wasn’t worth the marketing costs. Visio Corp. got purchased by Microsoft just before I retired, and I understand that it got rolled into the Office suite of products. I haven’t followed it since then. I did purchase one copy of Visio with the Microsoft branding in order to do a demonstration of the product for a talk I gave on the history of Visio. This was a motivational speech trying to convince some middle school students that studying STEM was valuable.

[Mark Davison]

Here are some particular questions for Mike Lopez:

1. What do you think of Lennard Zinn’s idea that you should replace carbon fiber forks every 10 years? Does that make any sense, or should pre-emptive replacement be based on hours of use, like aviation components? Or is pre-emptive replacement overkill?

2. How would you evaluate a used carbon fiber bike that you are considering purchasing? Does it need to be stripped and inspected ultrasonically in case the seller is lying about the whether the bike has been crashed?

3. Are there currently weight limits below which it is impossible to make a robust frame? Weights where it is possible but difficult?

4. Some commentators caution against buying a carbon fiber frame more than 10 years old. Are they saying that the expected service life of a carbon fiber frame is 10 years, or that carbon fiber frame production got much better after 2014? Would you recommend avoiding used carbon fiber bikes made before a certain date?

5. A common recommendation is to remove and inspect carbon fiber forks once a year to inspect for cracks. Does this make sense, or should the service interval be set by hours of use? Do you need to remove the crown race to be thorough?

[mstateglfr]

Originally Posted by Mark Davison

I'm going to continue to irritatingly use CFRP. The properties of the composite are not the same as the constituents, and I have noticed that the shortened form "carbon fiber" leads people to incorrect intuitions about the nature of the composite. For example, they believe that carbon fiber is inert, so that galvanic corrosion cannot occur in CFRP bicycles. They believe that carbon fibers are incredibly strong, so that a CFRP bicycle frame is inherently stronger than a steel one. They believe that CFRP cannot be sensitive to UV light exposure or chemical pollution, so CFRP frames should have an infinite shelf life, no matter how stored. Alas, the poor noble carbon fibers are embedded in lowly epoxy. Perhaps I should agree to call these composite frames "carbon fiber" half the time and "plastic" half the time.

I am purposely acting as a gadfly or devil's advocate in order to pull out comments from the real experts, as opposed to the CF fanboys.

You will continue to say 'cfrp'because when just 'cf' is used, people don't understand the material's limitations?
Bro, those same people won't suddenly understand the matrrial's limitations if you say 'cfrp'.

You saying 'cfrp' doesn't magically educate anyone on the material's capabilities and limitations. Based on your response, it seems like you think saying 'cfrp' will make a difference. Bless your heart. We all could type those 4 letters and it wouldn't make anyone more knowledgeable on the material.


Haha, keep tilting at windmills, I guess.

[Louis]

Well, we are now well into the Troll Zone.

I'm sure he would claim otherwise, but the OP isn't looking for real information, he's just trying to stir the pot.

[Mark Davison]

Originally Posted by fourflys

pretty sure this, from THE carbon expert on the forum, sums it up nicely.. if Mike Lopez's comments doesn't convince you, not sure why anyone else would engage (other than banter I guess)..

As for being afraid of the water:

I respect water. I learned how to swim and love swimming, but I avoid swimming when drunk, wear a lift vest when sailing, and have practiced rescue procedures for pulling in a sailor who has gone over the side.

I'm not a CFRP hater, and have a carbon fork on my Trek commuter bike, of all things.

I don't think I have been maintaining that fork properly, as it should probably be pulled and inspected carefully more than once every 10 years! (Commuter bikes typically don't get much love. They are useful, but unlovely. Mine is painted flat battleship gray, weighs far more than you would expect for an aluminum framed bike, and has an 8 speed IGH with apparently random spacing between the gears. )

As for other materials, I have read suggestions that even with a metal bike, you should periodically disassemble it completely, clean all the components, inspect for cracks, replace suspicious parts and reassemble.

I bought a stem from Cinelli recently, they are currently suggesting preemptive replacement, independent of inspection, based on hours of use.

My wife and I are seriously considering downsizing & having two small places instead, one here in Seattle and one near our only grandchild.
This may mean I'll have to go down to exactly 2 bikes--probably the Brompton and one travel bike. A candidate for the travel bike is a design with a titanium frame with S&S couplers, disk brakes and a CFRP fork, so I'll need to step up my game and learn how to maintain the fork properly, or just put up with the increased weight of a metal fork to simplify maintenance.

I know 2 other people who have had to downsize like this. They both chose Ritchey Break-away Outback frame sets, which are steel with a CF fork. This is an affordable commercial solution. Unfortunately the Outback frames have very short head tubes and an Outback wouldn't fit me.

As for buying used CF bikes--I'm intrigued by NHAero's experiment with buying a recent rim brake road racing bike. In my heart of hearts I would love to try a more recent race bike just to see what they feel like. Buy it, try it, sell it. Physics says it won't make me faster, but it might be fun.

[Mark Davison]

Just a note, the Thule website now has explicit discussions of which of their bike carriers are suitable for bikes with carbon fiber frames. It's interesting that some of their fork mount carriers are not recommended.

[AngryScientist]

Originally Posted by Louis

Well, we are now well into the Troll Zone.

I'm sure he would claim otherwise, but the OP isn't looking for real information, he's just trying to stir the pot.

Agreed.

I think we are done with this one. Some of the most knowledgeable people in the industry have chimed in, which is always appreciated.

I think we are past the point of productive discussion.